Tracheal couplings and associated systems and methods

ABSTRACT

The present invention relates to a tracheal coupling comprising a patient port 33, an outlet port 36, an inlet port 31 between the patient port and the outlet port, such that flow 34 from the inlet port can go to the patient port or direct to the outlet port, and a flow restriction e.g. 32 between the inlet port and the outlet port, or at the outlet port.

INCORPORATION BY REFERENCE TO PRIORITY APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference herein and made a partof the present disclosure.

FIELD OF INVENTION

The present invention relates to tracheal couplings (e.g.connectors/interfaces) for connecting/interfacing between an intubatedor tracheotomised spontaneously breathing patient and a gas supplyconduit from a continuous breathing gas supply.

SUMMARY OF THE INVENTION

An object of the invention is to provide a tracheal coupling which willat least go some way towards providing a useful choice.

In one aspect the present invention may be said to consist in a trachealcoupling for interfacing between a patient and a gases source, theconnector comprising a patient port for connecting to the tracheainterface/insert, an outlet port, and inlet port between patient portand outlet port for receiving a flow of gases from the gases flowsource, the connector restricting expiratory flow in use to produce PEEPof at least 1 cmH₂O when flow to the inlet port is 50 litres per minute.

Preferably the coupling is a connector that can be connected to atrachea interface/insert in or on a patient to interface between apatient and a gases source.

Preferably the trachea interface/insert is one or more of:

a trachea button, a endotracheal tube, a tacheostomy tube, a laryngealmask.

Alternatively the coupling comprises a trachea interface that can beattached to a patient to interface between a patient and a gases source.

Preferably the flow restriction includes a restriction between inletport and outlet port or at outlet port.

Preferably the flow restriction includes an adjustable orifice.

Preferably the flow restriction is caused by turbulence from inlet flow.

Preferably the flow restriction is caused by jetting air from inletflow.

Preferably the connector includes a nozzle extending from the inlet porttoward the patient port.

Preferably the nozzle extends through the patient port.

Preferably the nozzle includes a bend in a portion between an outlet endof the nozzle and the patient port.

Preferably the coupling further comprises a pressure relief valve.

Preferably the restriction comprises a heat and moisture exchanger.

In another aspect the present invention may be said to consist in asystem for supplying breathing gases to a patient comprising an airflowsource including an adjustable flow control, and a tracheal coupling forreceiving gases from the airflow source in excess for a patient'sbreathing requirements, supplying breathing gases for the patient toinhale, and releasing exhaled gases and uninhaled gases through anoutlet port, the connector restricting expiratory flow to generateamount of PEEP according to flow through connector, and therebyaccording to the setting of the adjustable flow control of the airflowsource.

Preferably the tracheal coupling is a connector that can be connected toa trachea interface/insert in or on a patient.

Preferably the trachea interface/insert is one of: a trachea button, aendotracheal tube, a tacheostomy tube, a laryngeal mask.

Preferably the coupling comprises a trachea interface that can beattached to a patient to interface between a patient and a gases source.

Preferably the flow restriction includes a restriction between an inletport and outlet port, or at the outlet port.

Preferably the flow restriction includes an adjustable orifice.

Preferably the system further comprises a pressure relief valve.

Preferably the flow restriction is caused by turbulence from inlet flow.

Preferably the flow restriction is caused by jetting air from inletflow.

Preferably the connector includes a nozzle extending from the inlet porttoward the patient port.

Preferably the nozzle extends through the patient port.

Preferably the nozzle includes a bend in a portion between an outlet endof the nozzle and the patient port.

In another aspect the present invention may be said to consist in atracheal coupling comprising a patient port, an outlet port, an inletport between the patient port and the outlet port, such that flow fromthe inlet port can go to the patient port or direct to the outlet port,and a flow restriction between the inlet port and the outlet port, or atthe outlet port.

Preferably the flow restriction includes an adjustable orifice.

Preferably the tracheal coupling further comprises a pressure reliefvalve.

In another aspect the present invention may be said to consist in atracheal coupling comprising a patient port, an outlet port, an inletport between the patient port and the outlet port, such that flow frominlet port can go to the patient port or direct to outlet port, and ajet or nozzle discharging flow from the inlet port toward the patientport in the flow path of gases flowing from the patient port to theoutlet port.

Preferably the tracheal coupling further comprises a restriction betweenthe inlet port and the outlet port, or at the outlet port.

Preferably the flow restriction includes an adjustable orifice.

Preferably the tracheal coupling further comprises a pressure reliefvalve.

In another aspect the present invention may be said to consist in amethod of providing breathing gases to a patient comprising: a)attaching a tracheal coupling to a breathing tube of the patient, thecoupling having a patient port, an outlet port, an inlet port betweenthe patient port and the outlet port, such that flow from inlet port cango to the patient port or direct to the outlet port, and a jet or nozzledischarging flow from the inlet port toward the patient port in the flowpath of gases flowing from the patient port to the outlet port, b)selecting a flow level for a supply of gases to the connector togenerate a desired amount of PEEP, c) supplying the flow level of gasesto the inlet port of the connector.

In another aspect the present invention may be said to consist in amethod of providing breathing gases to a patient comprising: a)attaching a tracheal coupling to a breathing tube of the patient, theconnector having a patient port, an outlet port, an inlet port betweenthe patient port and the outlet port, such that flow from inlet port cango to the patient port or direct to outlet port, and a jet or nozzledischarging flow from the inlet port toward the patient port in the flowpath of gases flowing from the patient port to the outlet port, b)adjusting a flow restriction for the connector according to an expectedflow of gases and a desired amount of PEEP c) supplying a flow of gasesto the inlet port of the connector.

In another aspect the present invention may be said to consist in aconnector for interfacing between an endotracheal tube or tracheostomytube and a gases source, the connector comprising a patient port forconnecting to the endotracheal or tracheostomy tube, an outlet port, andinlet port between patient port and outlet port for receiving a flow ofgases from the gases flow source, the connector restricting expiratoryflow in use to produce PEEP of at least 1 cmH₂O when flow to the inletport is 50 litres per minute.

In another aspect the present invention may be said to consist in asystem for supplying breathing gases to a patient fitted with anendotracheal or tracheostomy tube comprising an airflow source includingan adjustable flow control, and a connector receiving gases from theairflow source in excess for a patient's breathing requirements,supplying breathing gases for the patient to inhale, and releasingexhaled gases and uninhaled gases through an outlet port, the connectorrestricting expiratory flow to generate amount of PEEP according to flowthrough connector, and thereby according to the setting of theadjustable flow control of the airflow source.

In another aspect the present invention may be said to consist in atracheal connector comprising a patient port, an outlet port, an inletport between the patient port and the outlet port, such that flow fromthe inlet port can go to the patient port or direct to the outlet port,and a flow restriction between the inlet port and the outlet port, or atthe outlet port.

In another aspect the present invention may be said to consist in atracheal connector comprising a patient port, an outlet port, an inletport between the patient port and the outlet port, such that flow frominlet port can go to the patient port or direct to outlet port, and ajet or nozzle discharging flow from the inlet port toward the patientport in the flow path of gases flowing from the patient port to theoutlet port.

As used in this specification, “trachea connector” means a connectorcoupling between a gases supply conduit and the open end of atracheostomy tube or ET tube.

To those skilled in the art to which the invention relates, many changesin construction and widely differing embodiments and applications of theinvention will suggest themselves without departing from the scope ofthe invention as defined in the appended claims. The disclosures and thedescriptions herein are purely illustrative and are not intended to bein any sense limiting.

The term “comprising” is used in the specification and claims, means“consisting at least in part of”. When interpreting a statement in thisspecification and claims that includes “comprising”, features other thanthat or those prefaced by the term may also be present. Related termssuch as “comprise” and “comprises” are to be interpreted in the samemanner.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will be described with reference tothe accompanying drawings.

FIG. 1 illustrates a system for supplying breathing gases to atracheotomised patient.

FIGS. 2A and 2B illustrate a prior art trachea connector.

FIG. 2A illustrates the flow through the connector during patientinhalation.

FIG. 2B illustrates the flow through the connector during patientexhalation.

FIGS. 3A and 3B are cross sectional views of a trachea connectoraccording to one aspect of the present invention.

FIG. 3A illustrates flows through the connector during patientinhalation.

FIG. 3B illustrates flows through the connector during patientexhalation.

FIGS. 4A and 4B are cross sectional side elevations of a tracheaconnector according to a second aspect of the present invention.

FIG. 4A illustrates flows through the connector during patientinhalation.

FIG. 4B illustrates flows through the connector during patientexhalation.

FIG. 5 is a cross sectional side elevation of a trachea connectoraccording to a further aspect of the present invention where arestriction is provided intermediately located between the inlet portand the outlet port.

FIG. 6 is a cross sectional side elevation of a trachea connectoraccording to a further aspect of the present invention including anadjustable flow restriction.

FIG. 7 is a cross sectional side elevation of a trachea connectoraccording to a further aspect of the present invention including analternative adjustable restriction.

FIG. 8 is a cross sectional side elevation of a trachea connectoraccording to a further aspect of the present invention incorporatingflow restrictions in the form of a restricted outlet and ajet-generating nozzle.

FIG. 9 is a cross sectional side elevation of a trachea connectoraccording to a further aspect of the present invention illustrating thecombination of a turbulence-generating nozzle and a variable restrictedoutlet.

FIG. 10 is a cross sectional side elevation of a trachea connectoraccording to a further aspect of the present invention including anadjustable restricted outlet and a pressure relief valve.

FIG. 11 is a plot of pressure versus time illustrating the pressuregenerated at the internal end of the tracheostomy by three differenttracheal connectors under high flow supply conditions (50 litres perminute) used in conjunction with a lung simulator. Pressure generated atthe end of the tracheostomy tube in the patient airway of the prior arttracheal connector with no supply flow is also shown.

FIG. 12 is a cross sectional side elevation of a trachea connectoraccording to a further aspect of the present invention illustrating thecombination of a turbulence-generating nozzle and a sensor port.

FIG. 13 shows a trachea interface (mask).

FIG. 14 shows a stoma (trachea) button.

FIG. 15 shows a tracheostomy tube.

FIG. 16 shows an endotracheal tube.

FIG. 17 shows a trachea interface comprising a body and mask.

FIGS. 18 to 28 show various aspects of a trachea interface with a bodyand mask with PEEP control.

DETAILED DESCRIPTION

Tracheal couplings (e.g. in the form of connectors of tracheainterfaces) according to the present invention are intended to be usedin conjunction with the breathing gases supply system as generallydepicted in FIG. 1. A tracheal coupling provides for passage ofbreathing gases (e.g. oxygen)/interfacing between a high flow gasessupply and a patient (such as a tracheotomised or intubated patient.) Atracheal coupling can take the form of a connector that couples to atrachea insert/interface in or on a tracheotomised or intubated patient,either nasally or orally or otherwise. Alternatively, it can take theform of a trachea interface which can be attached to atracheotomised/intubated patient. The tracheal coupling can be used withother high flow gases sources, such as a supply of air from a walloutlet or ventilator. The tracheal couplings are intended for use in ahigh flow therapy situation (e.g., the gas supply exceeds peakinspiratory flow) where the patient is spontaneously breathing. Thismeans that a substantial proportion of the air supplied to the connectorvents directly to the room without being breathed by the patient.

FIG. 1 illustrates a system into which tracheal couplings in the form ofconnectors according to the present invention may be incorporated. Anexternal portion to a tracheostomy tube extends out of the neck ofpatient 1. A male connector 3 extends from the tracheostomy tube. Atrachea connector 4 includes a patient end 5 connected to the maleconnector 3 of the tracheostomy tube. The connector 4 includes outletend 6 and an inlet tube 7. The inlet tube is connected to the cuff 8 ofa breathing tube 10. The breathing tube includes a flexible conduit 9for supplying breathing gases to the patient. A cuff 11 at the other endof the breathing tube 10 is connected to outlet connector 12 of a gasesflow source. The gases flow source may be a flow generator 13. The flowgenerator 13 may include a humidification system includinghumidification chamber 14. Breathing gases can be delivered to the userat, or near, optimal temperature and humidity (37° C., 44 mg/L humidity)as the gases are delivered. Emulating the conditions within healthyadult lungs (37° C., 44 mg/L humidity) can help maintain healthymucociliary function in users with respiratory disorders affectingsecretion.

The flow generator 13 typically includes a blower receiving air from anair intake 15 and optionally oxygen from oxygen supply line 16. A userinterface may include a display screen 17 and user controls 18. The usercontrols may be in the form of buttons on the housing of the flowgenerator or combined with the display screen as a touch screen on theflow generator. An example flow generator for use in this application isthe Fisher & Paykel Healthcare AIRVO™. The flow generator includes aflow sensor and a feedback control which monitors the delivered flow andvaries the blower speed to maintain the output flow of the generator ata level set through the user controls.

The trachea connector 4 may also be used with the endotracheal tube (ETtube) of orally or nasally intubated patients. Endotracheal tubes andtracheostomy tubes are trachea inserts/interfaces. Other types oftrachea inserts/interfaces that a trachea connector can be used with orconnected to comprise stoma (trachea) buttons, and laryngeal masks.

Tracheal couplings in the form of trachea interfaces could also be usedwith the blower 17 and conduit 10 system shown in FIG. 1.

A prior art trachea coupling in the form of a connector is illustratedin FIGS. 2A and 2B. The connector includes an inner surface 22 at end 5for connecting over the outlet 3 of the tracheostomy tube, an outersurface 24 of inlet tube 7 for fitting inside the cuff 8 of thebreathing tube and an open outlet at end 6. The connector is for use ina high flow therapy where the patient is spontaneously breathing. Theconnector is not for use in a controlled mechanical ventilation. Theconnector is illustrated in FIG. 2A with typical flows during patientinhalation and in FIG. 2B with typical flows during patient exhalation.During patient inhalation, a portion 28 of inlet flow 26 flows directlyto outlet 20 of the connector. Another portion 29 of inlet flow 26 flowsto the patient through end 5. During exhalation, a flow 26 continues toenter the connector from the flow generator and, as indicated by arrows23 flows to the outlet 20 together with flow 27 being returned throughport 5 from the patient.

A prior art tracheal coupling (in the form of a connector) shown inFIGS. 2A and 2B provides an outlet port of about the same cross sectionas the inlet port and the patient port. In the high flow environment,the connector produces a very small pressure in the patient airway.Referring to FIG. 11, with a flow of 50 litres per minute, thisconnector produced a pressure as illustrated in section B of thepressure plot. In this section, maximum PEEP (Positive End ExpiratoryPressure) was less than 1 cmH₂O.

The tracheal couplings according to the present invention includeadaptations to work with the high flow environment (for example with theflow generator 13 in FIG. 1) to produce an elevated pressure in thepatient airway and PEEP. Because a large portion of the supplied gasesare exhausted direct to the room, there is a tolerance for variation inthe delivered flow rate. The tracheal couplings of the present inventionprovide a level of pressure support that varies depending on the flowrate delivered to the connector. The clinician can use variation of theflow rate supplied to the tracheal coupling of the present invention tovary the pressure support for the patient. Exhaust gas flow rates may beregulated by fixing the restriction to gas flow through variable ornon-variable adaptations. The end expiratory pressure experienced by auser can therefore be regulated. A positive end expiratory pressure(PEEP) can keep the airways and alveoli from collapsing atend-expiration and reopen airways and alveoli that have alreadycollapsed. The therapeutic provision of PEEP can improve gas exchange(decreased intra pulmonary shunt), reduce the resistance to airflow(lung resistance), and makes the lungs less stiff (increased lungcompliance). Levels of oxygen and carbon dioxide also may improve,reducing the need for supplemental oxygen and the sensation ofbreathlessness. PEEP may also improve cardiac performance by increasingmean intra thoracic pressure. PEEP is of special advantage to assistingin the treatment of obstructive lung diseases and heart failure,including emphysema, bronchiectasis, chronic bronchitis, cystic fibrosisand pulmonary edema.

A number of variations of tracheal couplings according to the presentinvention are illustrated in FIGS. 3A to 10, 12 and 17 to 28 anddescribed below. FIGS. 3A to 10, 12 show connectors, while FIGS. 17 to28 show trachea interfaces. These tracheal couplings can provide forinterfacing between a patient and gases supply. These tracheal couplingsinclude a range of features for producing an elevated internal pressurefrom the flow flowing through the tracheal couplings in order to providePEEP. The invention also contemplates tracheal couplings incorporatingmore than one of these adaptations. Examples of tracheal couplingsincorporating multiple adaptations are illustrated in FIGS. 6, 8 and 9and FIGS. 24, 26 and 27. Nonetheless, other combinations of thesefeatures are also possible and within the scope of the invention.

FIGS. 3A and 3B illustrate a tracheal coupling in the form of aconnector including a directed flow nozzle 30 extending from the inletport 31. The directed flow nozzle 30 includes an outlet end 32 facingtowards the patient port 33. The outlet end 32 of the nozzle 30 issmaller than the inlet port area and the inlet flow 34 acceleratesthrough the nozzle 30. During inhalation, a portion 35 of the flow 34flows directly to the outlet port 36. The remainder 37 flows through thepatient port 33 to be inhaled by the patient. As can be seen in FIG. 3B,when the patient exhales, the flow of exhaled gases 38 is opposed by theincoming gases 39. The opposed flows create a zone of turbulenceadjacent the nozzle outlet 32. This turbulent flow zone resists with thepatient exhalation flow 38 to create an elevated pressure at the patientport of the connector.

The flow nozzle could extend beyond patient port into tracheostomy tubeor other trachea insert/interface the connector is used with. This couldinclude a bend so that the nozzle turns the inlet flow into line withthe patient airway. The nozzle would not extend further than necessaryto make this turn For example, the portion in line with the patientairway would be no more than 30 mm long. So it would not irritate mucosain the trachea.

FIGS. 4A and 4B illustrate another connector including a flowrestriction at the outlet end. The flow restrictor may be in the form ofa wall partially closing the end of the connector. The wall includes anaperture 40 of a particular size, the area of the aperture 40 beingsmaller than the cross sectional area of the inlet port. Flow from theoutlet end of the connector is restricted by the port 40, producing aback pressure in the connector that is a function of the flow ratethrough the aperture.

As illustrated in FIG. 4A, during inhalation, a portion 41 of theincoming flow 42 flows directly to the aperture 40, while a portion 43is inhaled by the patient. As illustrated in FIG. 4B, during patientexhalation, all of the incoming air 42 and the exhaled air 44 combines,and the combined flow 45 flows through aperture 40.

This greater combined flow during exhalation leads to a greater pressurewithin the connector during patient exhalation. The aperture may besubstituted by multiple apertures, or a screen, mesh or filter.

In practice, a range of connectors may be provided with apertures 40 ofdifferent size (cross sectional area). A clinician may select aconnector from this range according to the flow and pressure supportneeds of their patient. For example, a connector with a certain aperturesize may be rated to provide a first pressure support with a first flowlevel, a second (greater) pressure support at a second (greater) flowlevel, a third (still greater) pressure support at a third (stillgreater) flow level and so on. Another connector with a larger aperturemay be rated to provide the first pressure support at the second flowlevel. Another connector with a smaller aperture may be rated to providethe second pressure support at the first flow level. The clinician,knowing the pressure support desired and the flow rated intended to beused, can select the connector with the closest matching pairing of flowand pressure. This selection could be facilitated by a chart of pressuresupport against flow, with each connector being represented in the chartin the form of a region or band. The clinician would select pressuresupport on one scale and flow on the other scale. The point on the chartindicated by these selections would fall in the region or band of aconnector suitable for supplying that combination of flow and pressuresupport.

FIG. 5 illustrates a variation of the connector of FIGS. 4A and 4B,including a fixed flow restricting aperture 50 at a locationintermediate between the inlet port and the outlet port. This aperture50 may be provided in a wall 51 within the connector. Alternatively theintermediate restriction could be provided by a neck in the surroundingwall 52 of the connector. The subsequent expanded portion 53 of theoutlet may allow other components with a male connector to be fitted tothe tracheal connector, with the portion 53 acting as a femaleinterface.

FIG. 6 illustrates a connector including an adjustable outlet aperture.The adjustable outlet aperture includes a primary aperture 60 in thewall of the connector. A cap 61 covers the outlet end 62 of theconnector. The cap 61 includes a tapered slot 63 at generally the samelongitudinal location as the aperture 60 when the cap 61 is fitted tothe connector. Rotation of the cap 61 changes the part of slot 63 whichintersects with aperture 60. More of less of the aperture 60 can beexposed to the internal portion of the connected, by rotation of the cap61 to adjust the amount of intersection of the slot 63 and the aperture60. Multiple apertures 60 may be provided on the outlet portion 62 ofthe connector and multiple slots on the cap 61.

Preferably the slot and aperture or slots and apertures are configuredso that for all positions of the cap there will be some outlet apertureexposed at all times, namely at least some intersection of the slot 63and the aperture 60 always exists.

The cap 61 may be retained on the end of the tracheal connector by anysuitable arrangement. In the illustrated arrangement, an outwardlyextending lip 64 at the end of the connector engages in an inwardlyextending channel of the cap 61. The cap 61 might be moulded, forexample, from a plastics material, or from an elastomeric material suchas silicone. An elastomeric material which would allow for internalundercuts to be moulded more easily. An elastomeric material would alsoprovide a frictional engagement on the connector to maintain therotational position of the cap.

FIG. 7 illustrates an alternative connector including an adjustableaperture. In this version, one or more primary apertures 70 are providedin the wall of the connector. A plug 71 may be adjusted into and out ofthe outlet end. An end portion of the plug partially overlaps the outletapertures 70 by a degree that varies according to the longitudinalposition of the plug.

In the illustrated arrangement the plug includes an external threadwhich engages with an internal thread in the outlet end 72 of theconnectors for adjusting the longitudinal position of plug 71. Rotationof the plug in a first direction draws the plug into the connector.Rotation of the plug in a second direction (relative to the connector)progressively withdraws the plug from the connector to progressivelyopen the outlet aperture.

Numerous alternative arrangements for providing an adjustable outletaperture may suggest themselves and be within the scope of the presentinvention. Many arrangements for providing a minimum flow aperture mayalso suggest themselves, for example, movement of any adjusting member(such as plug 71 of cap 61) may be limited so that at all times at leastpart of the primary outlet aperture remains uncovered. Alternatively oneor more additional by-pass outlets may be provided through the body ofthe connector, or through any adjusting member (such as through the endof cap 61 or through the body of plug 71).

The cap 61 of the embodiment of FIG. 6 may be reconfigured to be ahollow plug on the inside of the connector. Similarly, the plug 71 ofthe embodiment of FIG. 7 may be reconfigured to be a cap with a wallaround the outside of the connector. This could for example have athreaded wall like that shown in FIG. 9, or a frictional engagementportion like that shown in FIG. 6. Other arrangements for opening andclosing a flow passage by adjusting the position of a covering orclosing member may also be used, such as a ball cock or similar valve.

FIG. 8 illustrates a connector including a turbulent flow generator andan outlet restriction. The turbulent flow generator comprises nozzle 81extending from the inlet port 84 and directed toward the patient port85. The outlet flow restriction comprises an aperture 82 in end wall 83closing the outlet end of the connector. Of course, other forms ofadjustable flow restriction may be provided and other forms of turbulentflow generating nozzle. According to one example the nozzle may beconfigured to deliver a swirling or vortex flow into the tracheostomy orET tube or other trachea insert/interface that the connector isconnected to. This might have some benefit in clearing the airway of thetube.

FIG. 9 illustrates an arrangement including a turbulence generator and aflow restriction. In this case, the connector includes a turbulencegenerating nozzle 91 extending from the inlet port 98 toward the patientport 92. At the outlet end, the connector includes an adjustable flowrestriction in a form similar to the flow restriction of FIG. 7. Theadjustable flow restriction includes a primary aperture 93 and a cap 94which fits over the outlet end of the tracheal connector. The cap 94 isthreaded over the end of the tracheal connector and can be advanced orretreated along the body of the connector by rotating the cap relativeto the connector. Accordingly, the degree to which the cap 94 covers theprimary apertures 93 can be adjusted.

FIG. 10 illustrates a further embodiment of the tracheal connector. Thisembodiment includes a variable flow restriction of the type shown inFIG. 7 with a plug 101 fitted in the outlet end 102 of the trachealconnector. The plug covers a plurality of openings / outlet apertures103 to a degree that depends on how far the plug 101 is threaded intothe body of the connector.

In the embodiment of FIG. 10, the plug 101 includes a pressure reliefvalve, the pressure relief valve maybe in any suitable form, and couldalternatively be provided through the body of the connector in anysuitable location along the wall of the connector. The valve could bepassively activated or actively controlled, for example, by a solenoidenergisable by the flow generator or monitoring system.

In the embodiment illustrated the pressure relief valve includes apassage way 104 through the body of the plug 101. A valve member 105 isseated against a tapered surface 107 at the tracheal connector end ofthe passage 104. The valve member 105 is held against the seat 107 bypre-compression of a coil spring 108. The coil spring is held in itscompressed state by a cap 109 clipped onto the body of pipe 101. Thevalve member 105 may slide along a guide member 110 extending from thecover 109. The amount of pre-compression of spring 108 controls therelief pressure at which the valve member 105 withdraws from valve seat107.

Any other known form of pressure relief valve may be incorporated as analternative.

Each connector shown in FIGS. 3A to 10 could be adapted for interfacingwith a patient by connection to any type of trachea insert/interface,such as an endotracheal tube, tracheostomy tube, stoma (trachea) button,laryngeal mask or the like. FIGS. 13 to 16 show examples of each, whichare know in the art. A trachea interface 130 is a removable interfacethat can be attached to the neck of a patient with a tube for insertioninto the trachea, such as that shown in FIG. 13. A stoma button 140 ispermanently inserted into the trachea of a patient, such as that shownin FIG. 14. Tracheostomy tubes 150 and endotracheal tubes 160 areinserted further into the trachea, such as that shown in FIGS. 15 and 16respectively. The patient end of a connector can be coupled to a tracheainsert/interface in any suitable manner, for example by a friction pushfit. The term “trachea insert” or “trachea interface” can be usedinterchangeably to more generally refer to any of the abovementioned orother related apparatus.

FIG. 11 illustrates supporting pressure that can be generated using theillustrated tracheal connectors in a high flow supply environment. FIG.11 plots internal pressure at the open end of the tracheostomy tubeagainst time to show how the pressure varies during a patient breathingcycle. These plots were generated using sample connectors connected to alung simulator. The sample connector is supplied with inlet gases at theinlet port, from a gas supply set to deliver 50 litres per minute.

Portion A of the trace of FIG. 11 was generated by the prior artconnector similar to FIGS. 2A and 2B when supplied without flow. Thenegative pressures are the result of suction from the simulatedinhalations.

Portion B of the trace in FIG. 11 was generated using the prior artconnector with a flow of 50 litres per minute. It can be seen from thistrace that the average pressure support is approximately 0.5 cmH₂O andthe maximum expiratory back pressure is approximately 0.75 cmH₂O.

Portion C of the trace in FIG. 11 was generated using a connector havinga flow restricting orifice of a first size. In this connector, the flowrestricting orifice was 79 mm² cross section area, with the body of theconnector having an internal cross section of 165 mm². This connectorproduced a peak pressure support (PEEP) of approximately 2 cmH₂O.

Portion D of the trace in FIG. 11 was generated using a connector havinga flow restricting orifice of a second size. At this connector, the flowrestricting orifice was 24 mm² cross section area, with the body of theconnector having a cross section of 165 mm². This connector produced apeak pressure support (PEEP) of approximately 11 cmH₂O.

The general form of a trachea connector according to the presentinvention is described above. Within that general form wide variationsare possible but certain particulars are preferred.

The trachea connector preferably includes a socket at the patient portto connect with a male 15 mm medical connector typical of standardtracheostomy and ET tubes. Tracheostomy tubes conforming to ISO standard5366-1:2000 should have a permanently attached male 15 mm conicalconnector in accordance with ISO 5356-1.

The connector should be relatively small, for example with an overalllength of inlet tube of approximately 20 mm and overall length of maintube of approximately 40 mm. A range of length of inlet tube of 210 mmto 50 mm is contemplated. A range of length of main tube of 30 mm to 80mm is possible with the lower end of this range preferred. The innerdiameter of the main tube may be about 15 mm. The inner diameter of theinlet tube may be about 10 mm.

The inlet tube preferably intercepts with the main tube at an angle thatforms in an obtuse angle with the patient port and an acute angle withthe outlet port. An angle of about 60 degrees between the main tube andthe inlet tube may be appropriate.

As shown in FIG. 12, one or more additional ports 120 may be included onthe connector for use with sensors for monitoring properties of the gas.For example, potential sensors that could be usefully integrated withthe connector include a pressure sensor or a CO₂ sensor. In a medicalenvironment a standard luer port formed in a sidewall of the connectorwould be appropriate. A port for a CO₂ sensor or pressure sensor couldbe included anywhere along the wall of the main tube. The port 120 inFIG. 12 is shown on the embodiment of FIG. 3A by way of example. Itcould apply to any of the other embodiments in FIGS. 3B to 10, 12 and 17to 28.

The connector may be made from any suitable medical plastic or polymer.The plastic may be substantially rigid (by its material and detailedshape) so that it does not deform significantly under the fluctuatingpressure support generated by patient breathing.

The above describes preferred forms of the trachea connector accordingto the present invention. Widely differing embodiments will suggestthemselves to a person skilled in the art without departing from thescope of the invention as to finding appended claims.

The tracheal coupling could also take the form of a trachea interface172 that can be attached directly to a tracheotomised patient. Such acoupling is shown generally in FIG. 17. The trachea coupling comprisesan interface 170 such as that shown in FIG. 17 integrated with a bodyportion 171 such as any of those connector embodiments shown in FIGS. 3Ato 10. The tracheal coupling in the form of a trachea interface 172might further comprise an additional tube/coupling connected to thatpatient end that inserts into the trachea of a patient. Alternatively,the patient end of the trachea interface might insert directly into thetrachea.

Examples embodiments of tracheal couplings in the form of a tracheainterface 172 are shown in FIGS. 18 to 28. The body portion any of thoseembodiments could take the form of any of the connectors shown in FIGS.3A to 10, 12. The description for FIGS. 3A to 10, 12 applies to the bodyportion of the trachea interfaces shown in FIGS. 17 to 28.

As shown in FIG. 2, one or more additional ports 120 may be included onthe trachea interface for use with sensors for monitoring properties ofthe gas. For example, potential sensors that could be usefullyintegrated with the connector include a pressure sensor or a CO₂ sensor.In a medical environment a standard luer port formed in a sidewall ofthe connector would be appropriate. A port for a CO₂ sensor or pressuresensor could be included anywhere along the wall of the main tube. Theport 120 in FIG. 22 is shown on the embodiment 18 by way of example. Itcould applied to any of the other embodiments in FIGS. 17 to 28.

The trachea interface may be made from any suitable medical plastic orpolymer. The plastic may be substantially rigid (by its material anddetailed shape) so that it does not deform significantly under thefluctuating pressure support generated by patient breathing.

All the trachea couplings described herein can be used in conjunctionwith the blower 13 and conduit 10 system shown in FIG. 1

The above describes preferred forms of the trachea connector accordingto the present invention. Widely differing embodiments will suggestthemselves to a person skilled in the art without departing from thescope of the invention as to finding appended claims.

The invention claimed is:
 1. A method of providing breathing gases to apatient comprising: a) attaching a tracheal coupling to a breathing tubeof the patient, the coupling comprising: i) a patient port, ii) anoutlet port, iii) an inlet port between the patient port and the outletport, such that flow from the inlet port can go to the patient port anddirect to the outlet port, the inlet port discharging flow from anoutflow end of the inlet port toward the patient port in a flow path ofgases flowing from the patient port to the outlet port, and iv) a flowrestriction wherein the flow restriction includes a restriction betweenthe inlet port and the outlet port, or at the outlet port, the flowrestriction comprising an aperture and a blocking element, the aperturehaving an area smaller than a cross-sectional area of the outflow end ofthe inlet port, the blocking element configured to block a portion ofthe aperture; b) selecting a flow level for a supply of gases to thecoupling to generate a desired amount of PEEP; c) supplying the flowlevel of gases to the inlet port of the coupling; and d) adjusting theportion of the aperture blocked by the blocking element to generate thedesired amount of PEEP.
 2. The method of claim 1, further comprisingdirecting the flow level of gases from the inlet port toward the patientport with a nozzle that extends from the inlet port toward the patientport.
 3. The method of claim 2, wherein directing further comprisesbending the flow level of gases toward the patient port with a bend in aportion of the nozzle between an outlet end of the nozzle and the inletport.
 4. The method of claim 1, wherein supplying the flow level ofgases to the inlet port at a rate of 50 liters per minute produces aPEEP of at least 1 cm H₂O.
 5. The method of claim 1, further comprisingpassing the flow level of gases through the flow restriction.
 6. Themethod of claim 1 further comprising receiving the flow level of gasesat the inlet port in excess for the patient's breathing requirement. 7.The method of claim 1 further comprising releasing exhaled gases anduninhaled gases through the outlet port.
 8. The method of claim 1,further comprising directing, during an inhalation by the patient, afirst portion of the supplied flow directly through the outlet port anda second portion of the supplied flow through the patient port to beinhaled by the patient.
 9. The method of claim 8, further comprisingcombining, during an exhalation by the patient, all of the supplied flowand the expiratory flow, and directing the combined flow directlythrough the outlet port.
 10. The method of claim 1, further comprisingselecting the tracheal coupling from a plurality of tracheal couplings,wherein a first one of the plurality provides a first pressure supportat a first flow level and a second one of the plurality provides asecond pressure at the first flow level.
 11. The method of claim 10,wherein the tracheal coupling is selected based on a desired pressuresupport and a desired flow rate.
 12. A method of providing breathinggases to a patient comprising: a) attaching a connector to a breathingtube of the patient, the connector comprising: i) a patient port, ii) anoutlet port, iii) an inlet port comprising an outflow end, wherein anentirety of the outlet port is spaced from the outflow end along an axisof a wall extending between the patient port and the outlet port, theoutlet port located on an opposite side of the outflow end from thepatient port, and iv) a flow restriction wherein the flow restrictionincludes a restriction between the inlet port and the outlet port, or atthe outlet port, the flow restriction comprising an aperture and ablocking element, the aperture having an area smaller than across-sectional area of the outflow end of the inlet port, the blockingelement configured to block a portion of the aperture; b) selecting aflow level for a supply of gases to the connector to generate a desiredamount of PEEP; c) supplying the flow level of gases to the inlet portof the connector; and d) adjusting the portion of the aperture blockedby the blocking element to generate the desired amount of PEEP.
 13. Themethod of claim 12, wherein supplying the flow level of gases to theinlet port at a rate of 50 liters per minute produces a PEEP of at least1 cm H₂O.
 14. The method of claim 12, further comprising passing theflow level of gases through the flow restriction.
 15. The method ofclaim 12, further comprising receiving the flow level of gases at theinlet port in excess for the patient's breathing requirement.
 16. Themethod of claim 12, further comprising releasing exhaled gases anduninhaled gases through the outlet port.
 17. The method of claim 12,further comprising directing, during an inhalation by the patient, afirst portion of the supplied flow directly through the outlet port anda second portion of the supplied flow through the patient port to beinhaled by the patient.
 18. The method of claim 17, further comprisingcombining, during an exhalation by the patient, all of the supplied flowand the expiratory flow, and directing the combined flow directlythrough the outlet port.
 19. The method of claim 12, further comprisingselecting the tracheal coupling from a plurality of tracheal couplings,wherein a first one of the plurality provides a first pressure supportat a first flow level and a second one of the plurality provides asecond pressure at the first flow level.
 20. The method of claim 19,wherein the tracheal coupling is selected based on a desired pressuresupport and a desired flow rate.